Rotatable drill bit



Oct. 25, 1938. c. B. HOLT 2,134,164

ROTATABLE DRILL BIT Filed Jan. 31, 1938 3 Sheets-Sheet l Oct. 25, 1938.c. B. HOLT ROTATABLE DRILL BIT Filed Jan. 51, 1958 s Sheets-Sheet 2ATTOR N EYS Oct. 25, 1938. c B- HOLT 2,134,164

HOTATABLE DRILL BIT Filed Jan. 31, 1938 3 Sheets-Sheet 3 Patented Oct.25, 1938 UNITED STATES PATENT. OFFICE 3 Claims.

This invention relates to a rotatable drill bit especially adapted forcutting rock and other similar hard formations and is of the type setforth in my copending application filed July 29, 1937, and Serial No.156,391, wherein the rotatable bit body and the endless cuttingmechanism thereof is equipped with means whereby said endless cuttingmechanism will be hydraulically driven, the fluid exhausting therefrombeing employed to clean the cutting elements of the cutting mechanism ofcuttings and other foreign matter and acting to drive said cuttingsupwardly and out of the hole formed by'the drill bit.

With these and other objects in view, this invention consists in certainnovel features of construction, combination and arrangement of parts tobe hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had tothe following description and accompanying drawings, in which- Figure lis a side elevation illustrating a rotary drill bit constructed inaccordance with my invention.

Figure 2 is a side elevation, partly in section, showing one of thehalves of the body of the drill bit and with the endless cuttingmechanism thereon.

Figure 3 is a sectional view taken on the line 3-3 of Figure 1.

Figure 4 is a sectional view taken on the line 4-4 of Figure 3.

Figure 5 is a plan view showing one of the sprocket gears for theendless cutting mechanism.

Figure 6 is an edge elevation illustrating said sprocket gear.

Figure 7 is anend view illustrating a fluid operated wheel.

Figure 8 is a side elevation illustrating said wheel.

Figure 9 is a sectional view taken on line 9-9 of Figure 2.

Figure 10 is a sectional view taken on line I--Ill of Figure 2.

Figure 11 is a fragmentary edge elevation showing a modification of theendless cutting mechanism.

Figure 12 is a sectional view taken on the line I2I2 of Figure 11.

Referring in detail to the drawings, the numeral I indicates a rotarydrill bit having one end reduced and externally screw threaded to forman attaching shank 2 adapted to be threaded onto a drill rigging of anywell known construction. The other end of the body is rounded to presenta work end. The body also is composed of companion sections detachablyconnected by tie bolts 3. A fluid passage 4 extends through the shank 2and into the body terminat ing at one end into a chamber 5. Rotatablymounted in this chamber is a fluid operated wheel 6. The chamber opensoutwardly through the rounded end of the body. The fluid operated wheelis supported on a shaft I by antifriction roller bearings. The shaft Iis carried bythe body I. The fluid actuated wheel has secured to itsends end plates 8 defining sprocket gears overwhich is trained anendless cutting mechanism 9. As the endless cutting mechanism 9 travelsover the sprocket gears it is exposed at the rounded or work end of thebody so as to come in contact with the formations to be cut during therotation of the body I. Also journaled in a chamber I 0 of the body aresprocket gears II over which travels the endless cutting mechanism 9.Track channels I2 are provided in the body between the chambers I 0 and5 through which the runs of the endless cutting mechanism pass. Thesprocket gears II are secured on a shaft I3 supported by antifrictionbearings I4. The antifrlction bearings may be lubricated in any wellknown manner. The fluid passage 4 is branched, as shown at I5, to extendabout the chamber I0. Also the fluid passage has operating therein acheck valve I6. The fluid under pressure enters the passage 4 at theshank end 2 and escapes against the blades of the wheel. The fluid underpressure impinging against the blades of the wheel brings about rotationof the latter and consequently the driving of the endless cuttingmechanism 9. The cutting mechanism includes a plurality of rotatablecutters II, the shafts of which are connected by links I8. The shafts ofthe cutters engage in the notches of the sprocket gears 8.

The body I is provided with oppositely arranged recesses in which arejournaled reamers 2| acting to guide the body during the rotationthereof in a hole formed by the' endless cutting mechanism, besideshaving a reaming action upon the walls of the hole.

The fluid exhausing from the wheel or chamber 5 of said wheel contactsthe cutters and removes therefrom cuttings. Also, the fluid be-- ingunder pressure will drive the cuttings away from the work end of the bitand upwardly and out of the hole formed by the bit.

Instead of employing the links I8 for connecting the rotatable cuttersof the cutting mechanism, flexible cables 12 may be employed, as shownin Figures 11 and 12. In this modiflcation the cutters carry at the endsthereof cap-like elements 23 to engage in the notches oi the sprocketgears, the flexible elements 22 being secured to the cap-like elementsto connect the cutters in endles formation. The cutters are free torotate in the cap-like elements 23.

What is claimed is:

1. A rotary drill bit comprising a body including an attaching portionand a rounded work end and having a chamber in said end openingoutwardly therethrough, said body having a second chamber and guidegrooves connecting said chambers, a fluid actuated wheel Journaled inthe first chamber and including sprocket means, sprocket means journaledin the second chamber, and an endless cutting mechanism supported bysaid sprocket means and including a plurality of rotatable cuttersmovable outwardly of said body as they pass about the sprocket means ofsaid fluid actuated wheel, and means for admitting fluid under pressureinto the flrst chamber for driving the fluid actuated wheel andexhausting from said chamber through the cutting mechanism to removecuttings therefrom.

2. A rotary drill bit comprising a body including an attaching portionand a rounded work end and having a chamber in said end opening out- Iwardly therethrough, said body having a second chamber and guide groovesconnecting said chambers, a fluid actuated wheel journaled in the firstchamber and including sprocket means,

sprocket means journaled in the second chamber, an endless cuttingmechanism supported by said sprocket means and including a plurality oirotatable cutters movable outwardly of said body as they pass about thesprocket means of said fluid actuated wheel, said body having a fluidpassage adapted to be connected with s fluid pressure source andentering the first chamber to direct the fluid pressure on said wheelior driving the endless cutting mechanism and adapted to exhaust fromthe first chamber through the cutting mechanism to remove cuttings fromthe cutters thereof.

3. A rotary drill bit comprising a body including companion sectionshaving a fluid passage to receive fluid under pressure and having achamber opening outwardly through one end and provided with a secondchamber connected to the flrst chamber by guide grooves, sprocket gearsjournaled in said chambers, a fluid actuated wheel operating in thefirst chamber and connected to the sprocket gears therein, an endlesscutting mechanism traveling through said guide grooves and over thesprocket gears and moving outwardlyof the flrst chamber for cuttingpurposes, said body having a fluid passage entering the first chamber todirect fluid under pressure on said fluid actuated wheel for therotation thereof and the driving of the endless cutting mechanism, andreamers journaled on said body.

CLINTON B. HOLT.

